Conference paper

Drop of Activity of the Oxygen Electrode on the Base of Ag Catalyst (Polytetrafluorethylene)

M. Cenek ; Department of Electrotechnology, Faculty of Electrotechnical Engineering, Technical University, Brno, Czechoslovakia
O . Kouril ; Department of Electrotechnology, Faculty of Electrotechnical Engineering, Technical University, Brno, Czechoslovakia
J. Šandera ; Department of Electrotechnology, Faculty of Electrotechnical Engineering, Technical University, Brno, Czechoslovakia
J. Vanaček ; Department of Electrotechnology, Faculty of Electrotechnical Engineering, Technical University, Brno, Czechoslovakia

Abstract

The article describes the determination of the effect of
»impurities«, o,riginating from dissolution of the cell components,
upon the activity of the oxygen electrode Ag-catalyst .in 7 N
KOH. It was confirmed that the silver surface plays a more
serious part in electrochemical processes than it had been assumed
previously. It refers, above all, to the formation and solubility
of silver oxides and further to eventual adsorption of ions
[Ag(OH) 2]- on the active surface of the oxygen electrode silver
catalyst, especially with positive potentials in unloaded conditions.
For the determination of the total effect of events upon the
activity of the oxygen electrode, methods comparing the changes
of current density, in dependence on time, were applied. Current
density was measured with electrode potential of -300 mV vs.
Hg/HgO. The experiments proved that the activity of the oxygen
electrode on the base of Ag catalyst ~ PTFE in unloaded conditions
and without oxygen pressure in 7 N KOH at the approximate
temperature of 63° C, drops expressively with time. More
we observed the influence of the collector material construction,
effect of Zn, Ni, Cd and Fe, effect of amalgamation of the oxygen
electrode and effect of CO i- upon its activity. It was proved,
on the basis of experimental results, that the oxygen electrode
on the basis of Ag/PTFE is practically inapplicable. »Selfpoisoning
« occurs here probably due to the effect of ions [Ag(OH) 2]-.
On the other hand, the formation of [Ag(OH)2]- can be utilized
in the production technology of electron conductive skeleton of
the electrode by the application of a mixture of silver and electronegative
metal, e. g. Zn.

Keywords

Hrčak ID:

197284

URI

https://hrcak.srce.hr/197284

Publication date:

15.5.1972.

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